1. Field
The present Application relates generally to the operation of communication systems, and more particularly, to a system for signaling the availability of a device to receive forward data in a communication network.
2. Background
Advances in technology have provided for increased automation in many industries. For example, in the shipping industry, technology has allowed for the shipment and delivery of cargo virtually around the clock. Delivery vehicles now carry and deliver cargo to all parts of the country. For example, in the trucking industry, cargo-carrying tractor-trailers may be driven hundreds or thousands of miles to reach a delivery site. In some cases, a delivery vehicle may make several intermediate stops before reaching its final destination. Thus, with the expansion of delivery schedules and routes, it has become increasingly important for vehicle communication systems to maintain and/or establish communications. With remote central stations to provide status reports or other information.
Typically, delivery vehicles include self contained communication devices that provide for transmission of information to a central station. For example, a vehicle may report its current position, cargo state, engine parameters or other information to a central station. To provide these communications, major service providers with complete communication networks, such as commonly available nationwide telecommunication networks, are used to obtain communications between vehicles and a central station. However, in some regions of the country, for example, at the border regions, coverage provided by these serving systems may be limited. Thus, some delivery systems utilize specialized serving communication networks to supplement of the coverage of serving system with a national communication network. These specialized networks utilize special hardware and/or additional systems to provide coverage over a large region. For example, as a vehicle approaches the border with another country, such a specialized network may be used to provide communications between the vehicle and a central station because the primary network may have limited coverage in that region.
During operation of a delivery vehicle, it is desirable to establish communication with the vehicle using either a national serving system or a specialized serving system network. However, a vehicle's communicating device may go into a sleep mode to conserve power. Usually, the sleep mode is scheduled to occur at periodic intervals. During sleep mode, communications with the vehicle cannot occur. When the device wakes up, it may attempt to communicate over the primary network to receive information from the central station. However, if the device for some reason cannot communicate over the primary network, it may attempt to communicate over the specialized communications network.
Unfortunately, the central station may not know whether the vehicle and its communication device are in coverage on the national serving system, the specialized serving system, or outside all coverage areas. Conventional systems may not determine when a device is listening for communications on their network. Thus, the central station may not know if the communication device is attempting to listen to messages on the specialized serving system network.
Therefore, what is needed is a method and a system that is able to initiate communications with the mobile station over either communication network. This embodiment of this invention improves coverage area so the mobile station can determine which serving system to listen for incoming traffic on.